Mouse Model Of Cardiac Dysfunction Research Articles

Pterostilbene attenuates heart failure by inhibiting myocardial ferroptosis through SIRT1/GSK-3β/GPX4 signaling pathway

Sustained myocardial injury due to hypertension and diabetes mellitus leads to production of endogenous reactive oxygen species (ROS) and insufficient myocardial antioxidant capacity, increasing the risk of cardiomyocyte ferroptosis. Ferroptosis is a nonapoptotic form of cell death driven by unrestricted lipid peroxidation. Dysfunction of the glutathione peroxidase 4 (GPX4) antioxidant system also plays an important role in ferroptosis. Cardiomyocyte ferroptosis ultimately leads to myocardial deterioration, such as inflammation, fibrosis, and cardiac remodeling, resulting in structural and functional changes. Pterostilbene (PTS), a demethylated derivative of resveratrol, exhibits strong anti-inflammatory and antioxidative activities. In this study, we used in vitro experiments to explore ferroptosis induced by angiotensin II (Ang II) of primary cardiac myocytes (CMs) and in vivo experiments to prepare a transverse aortic constriction (TAC)-induced cardiac dysfunction mouse model. PTS can significantly ameliorate Ang II-induced cardiomyocyte ferroptosis in vitro and reduce cardiac remodeling, while improving cardiac function in mice after TAC in vivo. Further mechanistic investigations revealed that PTS exerts its protective effect through the SIRT1/GSK-3β/GPX4 pathway. After siRNA-mediated knockdown of SIRT1 or GPX4 in CMs, the protective effects of PTS on cardiomyocytes were abolished. This study provides important theoretical support for the potential of PTS to attenuate pathological cardiac remodeling and heart failure and provides a preliminary exploration of the molecular pathways involved in its protective mechanism.

Abstract P2139: The Adiponectin Receptor Agonist ALY688 Prevents Pressure Overload-induced Cardiac Dysfunction And Adverse Cardiac Remodeling

Adiponectin has been shown to mediate multiple cardioprotective effects. Since the use of adiponectin protein as a practical therapeutic is associated with multiple challenges, we examined the functional significance of targeting adiponectin signaling with ALY688, a small peptide-based adiponectin mimetic, in a mouse model of cardiac dysfunction caused by left ventricular pressure overload (PO) induced by minimally invasive transverse aortic banding (MTAB). Following daily administration of ALY688 over 5 weeks after induction of PO, echocardiography showed that significantly attenuated PO-induced reduction in ejection fraction and other indices of cardiac function compared with vehicle. ALY688 also significantly reduced cardiac hypertrophic remodeling (heart weight-to-tibia length), cardiomyocyte cross sectional area, and myocardial and circulating levels of serum natriuretic peptide A. ALY688 reduced PO-induced increases in myofibroblasts, and scar tissue collagen content based upon immunofluorescence staining for α-smooth muscle actin and vimentin, scanning electron microscopy, and picrosirius red staining. ALY688 reduced PO-induced myocardial expression of 14 pro-inflammatory genes and circulating IL-12, IL-15, IL-17, and MIP-3α levels. Targeted metabolomics revealed that ALY688 increased myocardial fatty acid oxidation, with increased mobilization of cardiac triacylglycerols and a decrease in sphingomyelin, fatty acids and lysophospholipids. In conclusion, the adiponectin analogue ALY688 is cardioprotective in a preclinical animal model of heart failure and cardiac remodeling, with beneficial metabolic, anti-fibrotic, anti-hypertrophic and anti-inflammatory properties leading to improved cardiac function.

Neferine Ameliorates Sepsis-Induced Myocardial Dysfunction Through Anti-Apoptotic and Antioxidative Effects by Regulating the PI3K/AKT/mTOR Signaling Pathway.

Septic cardiomyopathy is a common complication of severe sepsis, which is one of the leading causes of death in intensive care units. Therefore, finding an effective therapy target is urgent. Neferine is an alkaloid extracted from the green embryos of mature seeds of Nelumbo nucifera Gaertn., which has been reported to exhibit various biological activities and pharmacological properties. This study aims to explore the protective effects of neferine against lipopolysaccharide (LPS)-induced myocardial dysfunction and its mechanisms. The LPS-induced cardiac dysfunction mouse model was employed to investigate the protective effects of neferine. In this study, we demonstrated that neferine remarkably improved cardiac function and survival rate and ameliorated morphological damage to heart tissue in LPS-induced mice. Neferine also improved cell viability and mitochondrial function and reduced cell apoptosis and the production of reactive oxygen species in LPS-treated H9c2 cells. In addition, neferine significantly upregulated Bcl-2 expression and suppressed cleaved caspase 3 activity in LPS-induced mouse heart tissue and H9c2 cells. Furthermore, neferine also upregulated the phosphatidylinositol 3-kinase/protein kinase B/mechanistic target of rapamycin (PI3K/AKT/mTOR) signaling pathway in vivo and in vitro. Conversely, LY294002 (a PI3K inhibitor) reversed the protective effect of neferine in LPS-induced H9c2 cells. Our findings thus demonstrate that neferine ameliorates LPS-induced cardiac dysfunction by activating the PI3K/AKT/mTOR signaling pathway and presents a promising therapeutic agent for the treatment of LPS-induced cardiac dysfunction.

Shikonin Ameliorates LPS-Induced Cardiac Dysfunction by SIRT1-Dependent Inhibition of NLRP3 Inflammasome.

Shikonin (SHI) is an anti-inflammatory agent extracted from natural herbs. It is still unknown whether SHI ameliorates lipopolysaccharide (LPS)-induced cardiac dysfunction. This study aims to explore the protective effects of SHI on LPS-induced myocardial injury and its mechanism. The LPS-induced cardiac dysfunction mouse model was employed to investigate the protective effects of SHI. In the present study, we found that SHI treatment improved the survival rate and cardiac function and remarkably ameliorated the release of inflammatory cytokines and macrophage infiltration in heart tissue of LPS-treated mice. SHI also reduced lactate dehydrogenase (LDH) and cardiac troponin (cTn) release, cell inflammation, and apoptosis in LPS plus adenosine triphosphate (ATP)-treated H9c2 cells. In addition, SHI significantly upregulated silent information regulator 1 (SIRT1) expression and suppressed the upregulation of NOD-like receptor protein 3 (NLRP3), cleaved caspase-1, and caspase-1 activity in heart tissues induced by LPS. Meanwhile, we got the same results in LPS plus ATP-treated H9c2 cells in vitro. Further, SIRT1 inhibitor or siRNA partially blocked SHI-mediated upregulation of SIRT1 expression and downregulation of NLRP3, cleaved caspase-1, and caspase-1 activity in heart tissues induced by LPS. Therefore, we conclude that SHI ameliorates LPS-induced cardiac dysfunction by inhibiting SIRT1-dependent activation of NLRP3 inflammasomes and might be a promising therapeutic strategy for the treatment of LPS-induced cardiac dysfunction.

Helium Protects Against Lipopolysaccharide-Induced Cardiac Dysfunction in Mice via Suppressing Toll-Like Receptor 4-Nuclear Factor κB-Tumor Necrosis Factor-Alpha/ Interleukin-18 Signaling.

The nonanesthetic noble gas helium (He) can protect many organs against ischemia and reperfusion injury, such as liver and heart. However, the role of He on cardiac dysfunction during sepsis is not clear. In this study, we established a lipopolysaccharide (LPS)-induced cardiac dysfunction mouse model to examine the influence of He on the impaired cardiac function, and further investigated the possible innate immune mechanisms that may be involved. LPS induced left ventricular dysfunction and cavity enlargement, as indicated by decreased percent ejection fraction, percent fractional shortening, left ventricular anterior wall thickness in systole, and left ventricular posterior wall thickness in systole, while increased left ventricular end-systolic diameter and left ventricular end-systolic volume. He improved the impaired left ventricular function and cavity enlargement in a dose-dependent manner, and it was beneficial at 1.0 mL/100 g. Mechanistically, He inhibited toll-like receptor 4 (TLR4) expression, reduced the phosphorylation of nuclear factor κB (NF-κB), and subsequently alleviated tumor necrosis factor-alpha (TNF-α) and interleukin-18 (IL-18) expression in heart. Therefore, He protects against LPS-induced cardiac dysfunction in mice partially via inhibiting myocardial TLR4-NF-κB-TNF-α/IL-18 signaling.

Potentially Critical Roles of NDUFB5, TIMMDC1, and VDAC3 in the Progression of Septic Cardiomyopathy Through Integrated Bioinformatics Analysis.

Septic cardiomyopathy (SC) is a rare and harmful cardiovascular disease with decreased left ventricular (LV) output and multiple organ failure, which poses a serious threat to human life. Despite the advances in SC, its diagnostic basis and treatment methods are limited, and the specific diagnostic biomarkers and its candidate regulatory targets have not yet been fully established. In this study, the GSE79962 gene expression profile was retrieved, with 20 patients with SC and 11 healthy donors as control. Weighted gene coexpression network analysis (WGCNA) was employed to investigate gene modules that were strongly correlated with clinical phenotypes. Blue module was found to be most significantly related to SC. Moreover, Gene Ontology (GO) functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed on the coexpression genes in blue module and showed that it was associated with metabolic pathways, oxidative phosphorylation, and cardiac muscle contraction. Furthermore, a total of 10 hub genes NDUFB5, TIMMDC1, VDAC3, COQ10A, MRPL16 (mitochondrial ribosomal protein L16), C3orf43, TMEM182, DLAT, NDUFA8, and PDHB (pyruvate dehydrogenase E1 beta subunit) in the blue module were identified at transcriptional level and further validated at translational level in myocardium of an lipopolysaccharide-induced septic cardiac dysfunction mouse model. Overall, the results of quantitative real-time polymerase chain reaction were consistent with most of the microarray analysis results. Intriguingly, we observed that the highest change was NDUFB5, TIMMDC1, and VDAC3. These identified and validated genes provided references that would advance the understanding of molecular mechanisms of SC. Taken together, using WGCNA, the hub genes NDUFB5, TIMMDC1, and VDAC3 might serve as potential biomarkers for diagnosis and/or therapeutic targets for precise treatment of SC in the future.

BIOLOGICAL AGE INFLUENCES HEART FAILURE PATHOGENESIS

Heart failure (HF) impacts patients of all ages and is an enormous public health problem. Historically, HF has been treated with a single, multi-purpose approach, despite the observation that biological differences such as age influence HF pathogenesis and therapeutic outcomes. We hypothesized that HF pathogenesis differs across the life-course, a hypothesis which we tested with a mouse model of cardiac dysfunction at three distinct stages of life. C57BL/6 mice at pediatric (5 weeks), adult (3-5 months), and old (18 months) ages were treated with a mini-osmotic pump that eluted isoproterenol (ISO; 30mg/kg/hour) for six days. As expected, cardiovascular morbidity and mortality were significantly worse in the old group. Both pediatric and adult underwent hypertrophic remodeling, as evident by higher LV weight relative to tibia length (TL). However, ISO exposure did not increase LV/TL in old mice. We performed RNA-sequencing to understand pathways and genes differentially regulated by age. 119, 1515, and 33 genes were significantly differentially expressed in pediatric, adult, and old mice exposed to ISO, respectively. Of these, only 2 transcripts were upregulated in response to ISO across all three ages. Expression of pro-fibrotic mediators differed across the life-course, with adults inducing a pro-fibrotic transcriptional program (α-smooth muscle actin, fibronectin, collagen, periostin) that was attenuated in old and absent in pediatric animals. Our data clearly demonstrates that pediatric, adult, and aged hearts activate distinct molecular remodeling in response to ISO, highlighting the significance of age as a biological variable in HF pathogenesis.

Abstract 87: Loss of Mir-155 Attenuates Sepsis Induced Cardiac Dysfunction

Objective: Sepsis induced cardiac dysfunction is featured by inflammation and metabolic repression. miR-155 is a typical multifunctional miRNA and loss of miR-155 has been shown to protect the heart from pathological cardiac hypertrophy while increased miR-155 could promote the formation of foam cell in atherogenesis. However, the role of miR-155 in sepsis induced cardiac dysfunction is unclear. Methods: E.coli lipopolysaccharide (LPS) (5mg/kg) was administered to C57BL/6 mice to create a sepsis-induced cardiac dysfunction model. Cardiac function was assessed by echocardiography 5-6 h post-LPS administration. Heart tissues were collected within 7-9 h after LPS treatment for the analysis of gene expressions. Tail vein injection of miR-155 antagomir (80mg/kg/d) or miR-155 agomirs (30mg/kg/d) for 3 consecutive days were used to decrease or increase miR-155 expressions in heart. Results: LPS induced a reduction of 15% in fractional shortening (%FS) and 25% in ejection fraction (%EF). Expression of miR-155 was increased by 2 fold in sepsis-induced cardiac dysfunction mouse model. Over-expression of miR-155 agomirs led to a decrease of 5% in FS and 10% in EF as compared to scramble controls. Aggravation of LPS induced cardiac dysfunction by miR-155 agomir was not associated with alteration in inflammation or cardiac metabolism. However, miR-155 agomir increased LPS- induced myocardium apoptosis and also elevated the ratio of Bax/Bcl-2 at the protein level. Intravenous injection of cholesterol-modified antisense oligonucleorides antagomirs of miR-155 markedly rescued the LPS induced heart failure and apoptosis. Western bloting indicated that miR-155 overexpression in vivo led to a significant inhibition of Pea15a while miR-155 knock-down caused a significant upregulation of Pea15a, indicating that Pea15a was a potential target gene of miR-155. Interestingly, plasma miR-155 levels were also found to be significantly increased in critically ill patients with sepsis compared to healthy controls. Conclusion: This study demonstrates that miR-155 regulates sepsis induced cardiac dysfunction and Pea15a is a potential targer gene of miR-155. Loss of miR-155 represents a novel therapeutic method for sepsis induced cardiac dysfunction

An Analysis of the Myocardial Transcriptome in a Mouse Model of Cardiac Dysfunction with Decreased Cholinergic Neurotransmission

Autonomic dysfunction is observed in many cardiovascular diseases and contributes to cardiac remodeling and heart disease. We previously reported that a decrease in the expression levels of the vesicular acetylcholine transporter (VAChT) in genetically-modified homozygous mice (VAChT KDHOM) leads to decreased cholinergic tone, autonomic imbalance and a phenotype resembling cardiac dysfunction. In order to further understand the molecular changes resulting from chronic long-term decrease in parasympathetic tone, we undertook a transcriptome-based, microarray-driven approach to analyze gene expression changes in ventricular tissue from VAChT KDHOM mice. We demonstrate that a decrease in cholinergic tone is associated with alterations in gene expression in mutant hearts, which might contribute to increased ROS levels observed in these cardiomyocytes. In contrast, in another model of cardiac remodeling and autonomic imbalance, induced through chronic isoproterenol treatment to increase sympathetic drive, these genes did not appear to be altered in a pattern similar to that observed in VAChT KDHOM hearts. These data suggest the importance of maintaining a fine balance between the two branches of the autonomic nervous system and the significance of absolute levels of cholinergic tone in proper cardiac function.

Myocardial infarction and cardiac remodelling in mice.

We established a mouse model of cardiac dysfunction due to myocardial infarction (MI). For this we ligated the left anterior descending coronary artery in male C57BL/6J mice and assessed healing and left ventricular (LV) remodelling at 1, 2 and 4 days and 1, 2 and 4 weeks after MI. Echocardiography was performed at 1 and 2 weeks and 1, 2, 4 and 6 months after MI. We found that neutrophil infiltration of the infarct border was noticeable at 1-2 days. Marked macrophage infiltration occurred at day 4, while lymphocyte infiltration was apparent at 7-14 days. Massive proliferation of fibroblasts and collagen accumulation began by day 7-14, and scar formation was completed by day 21. LV diastolic dimension increased markedly at 2 weeks and remained at the same level thereafter. LV shortening fraction decreased significantly at 2 weeks and then slowly decreased. In non-infarcted areas of the LV, myocyte cross-sectional area and interstitial collagen fraction increased progressively, reaching a maximum at 4 months. This study provides important qualitative and quantitative information about the natural history of cardiac remodelling after MI in mice.